Motivation, Objectives, Methods

Motivation

NC corn growers are rightly concerned that insufficient nutrient levels may become limiting at high yield, especially under irrigation. Some growers are regularly achieving yields of 200 bu/acre, and some NC Corn Yield Contest leaders have attained historic yields of 300 to 350 bu/acre. The recent world-record yields, 504 bu/acre in Georgia in 2014 and 532 bu/acre in Virginia in 2015, were realized in environments and soils similar to ours, leaving little doubt that NC corn yield potential is similarly high. Some question whether NC Dept. of Agriculture and Consumer Services (NCDA&CS) fertilizer recommendations are adequate in face of today’s high-yielding varieties and management. This study was conceived to add value to the NC Corn Yield Contest by studying the nutrient status of Contest entries and the soils that produced them.

Objectives: Answer the following Questions:

1) Are macro- and micronutrient deficiencies apparent at high yield and become yield limiting?
2) Do tissue nutrient levels need to be within established sufficiency ranges to produce high yield?
3) What are the apparent nutrient-use efficiencies at high yield?
4) With high yields, what are the relationships among: tissue nutrient levels; nutrient-use efficiency; soil type and chemical properties; and management factors such as irrigation, tillage, hybrid, row width, plant population, and fertilization?
5) What is the temporal variability in NCDA&CS soil test results and fertilizer recommendations.

Methods

1) Sample corn tissue and soil from areas that collaborating growers are managing for entry into the 2018 Yield Contest
2) Sample at four growth stages commonly used for deficiency analysis: seedling/early, early, tasseling, and maturity
3) Encourage collaborators to assist with sampling, enabling inclusion of more growers, making the study more robust
4) Submit samples to the NCDA&CS Agronomic Division Laboratories. Project will cover costs of sampling and analysis
5) Repeat for 2019 Corn Yield Contest?
6) Analyze the data and publicize the results to growers, Extension Agents, Regional Agronomists, consultants, and NCDA&CS Agronomic Services Division